FIGURE 1. Fossil eggs from Taung, T92-88 on the right and T93-17 on the left.
FIGURE 2. All specimens, both extant eggs and fossil eggshells, showing surface morphology at 6.3X magnification.
FIGURE 3. All specimens, both extant eggs and fossil eggshells, showing surface morphology at 12.5X magnification.
FIGURE 4. All specimens, both extant eggs and fossil eggshells, showing surface morphology at 57X magnification.
FIGURE 5. Renderings of fossil eggshell fragments embedded in matrix ( 1 - 2) and indication of the internal boundary between eggshell and matrix ( 3 - 4). Images 1 and 3 are fossil eggshell fragment T92-88, and images 2 and 4 are fossil eggshell fragment T93-17. Note the relatively consistent thickness at the edges and how this maintained surface curvatures indicated by the external surfaces.
FIGURE 6. Fossil eggshell fragments T92-88 (blue) and T93-17 (yellow) fit to eggs from five extant birds. Fits depicted visually in the figure (rigidly constrained size) correspond to root mean square (RMS) values reported in Table 2. Note that visual correspondence supports quantification of RMS values in that fossil eggshell fragment T92-88 fits best with the blunt pole of the extant guinea fowl egg. Extant black eagle (blunt pole) and giant eagle owl (apical pole) eggs provide the next closest, but still worse fits. Fossil eggshell fragment T93-17 fits best with the equatorial region of the black eagle egg. The extant guinea fowl egg provides the next closest fit for fossil eggshell fragment T93-17.
FIGURE 7. Representative SEM results from one (TDES 3) of the fossil eggshells.
FIGURE 8. (1) Fossilized eggshell fragments T92-88 (blue) and T93-17 (yellow) indicating best fit to the same black eagle egg as illustrated in Figure 6, plus six additional black eagle eggs. Note despite intraspecific variability in egg shape, the fits are quite similar (also see Table 3). This suggests even accounting for intraspecific variability in egg shape Results in Table 2 should be robust. (2) Fossil eggshell fragments T92-88 (blue) and T93-17 (yellow) indicating best fit to the same guinea fowl egg as illustrated in Figure 6 (far left), plus four additional guinea fowl eggs. Note that despite intraspecific variability in egg shape, the fits are quite consistent (also see Table 3). This suggests that even accounting for intraspecific variability in egg shape results of the surface curvature analyses are robust.
FIGURE 9. Cross-plot of oxygen and carbon isotope values from fossil eggshells and sediment, base of the Dart Pinnacle, Taung. There is a high degree of consistency between replicate samples, and each eggshell fragment shows a distinct isotopic signature, indicating that the eggshells are derived from different individuals (with the possible exception of TDES 2 & TDES 3). The δ13C values indicate that all eggshells have a predominantly C4 (savannah grass) dietary signal, with the exception of T93-17 which has a pure (or almost pure) C3 diet.
